The Spatial Distribution Analysis Of Argentine Hake (Merluccius Hubbsi) Fishery Stock In The Southwest Atlantic

The Argentine hake（Merluccius hubbsi）fishery is one of the long-history,most productive and largest fisheries in the Southwest Atlantic,which is mainly fished by large deep-sea trawls.After conservation and management measures have been made for over 20 years,the Argentine hake stock has gradually recovered,with an average annual catch of approximately 300,000 tonnes in recent years.In 2014,Altamare S.A.in Puerto Madryn,Chubut,Argentina,a subsidiary of Shanghai Jinyou Deep Sea Fisheries Co Ltd,which owns a cod deep-sea trawler（Puente Mayor）,making it the first Chinese company to hold a quota for Argentine hake.The study is based on the 2019-2021 fishing logbook data from trawler Puente Mayor,official information from the Argentine Ministry of Agriculture,Livestock and Fisheries and the marine environmental parameters SSS,SST,Chl-a,SWS from the National Oceanic and Atmospheric Administration（NOAA）of the U.S.The results are presented as follows.（1）According to the annual reports of SAGPyA,the annual catches by southern fishery around the 41°S from 2013 to 2021 range from 231,500 tonnes to 272,300 tonnes;the average annual CPUE ranges from 15.61t/d to 21.68t/d.According to the data published by NOAA,in the spawning grounds of the hake during 2013-2021 mean sea surface temperature（SST）range between 13.90℃ and 14.83℃.Mean sea surface salinity（SSS）range between 33.03psu and 33.47psu.Chlorophyll concentrationa（Chl-a）range between 1.94mg/m³ and 2.55mg/m³ and sea surface wind speed（SWS）range between 8.02m/s and 9.06 m/s.By assuming that there is a correlation between the environmental factors of spawning grounds and the fluctuation of annual average CPUE of fishing grounds,the models of hake catch variation based on environmental factors SSS,SST,Chl-a,and SWS were established to verify the hypotheses,and the results showed that the changes of marine environment and catch fluctuation showed some extent degrees of correlation.It is noted that the catch prediction results of Schaefer’s formula based on SSS had the smallest error and relatively better explanatory power for the formula,with the following mathematical expressions.（P<0.05,R₂=0.5392）D_sss=33.52d_t-1.1322 d_t²+（-4.7709×HSSS+158.68）× d_tIn the equation,D_sss means the predicted catch based on sea surface salinity,d_t means the fishing effort in year t,and H_sss means the average sea surface salinity of the spawning grounds during the spawning period in year t.Thus,the range of maximum sustainable yield（MSY）based on SSS is obtained 22.80 × 104 tons to 26.68 × 104 tons.The corresponding range of maximum sustainable fishing effort（dMSY）is obtained as 14.19 × 103 days to 15.35 × 103 days.（2）A three-year catch center distribution study provided by trawler-Puente Mayor owned by fishing company Altamare S.A.Fisheries’ from 2019 to 2021 is conducted with the following results,latitude and longitude operating ranges are concentrated at 41°S～520 S,58°W～67°W.Optimal fishing ranges are centered at 42°S～44°S,46°S～49°S,59°W～64°W.Optimal fishing months are attributed to July to October.The distribution range of catch centers located at 41°50′S～50°16′S,59°51′W～65°53′W.Catch centers are mainly concentrated in 60°W～63°W in longitude and 45°S～48°S in latitude.The center of production has obvious quarterly distribution pattern,generally from January to June each year.The catch center gradually shifts from northeast to southwest offshore,while from July to December each year.The center of production gradually moves from southwest to northeast at deep sea.In terms of the dominant weight distribution,the weight distribution ranged from 120g to 3500g,accounting for 59.83%of Argentine hake in the range of 250g-500g,and the proportion of small-size individuals was higher along both the coast areas and in the EEZ range.As the weight increased,large-size individuals appeared further offshore in the northeast.（3）This chapter is translated and summarized by literature method,and the regulations related to the management of hake fishery in Argentina are studied,and the development and current situation of hake fishery management are analyzed.It is concluded that Argentina has formed a stable fishery management model and the relevant institutions are well established.Argentina has a good environment for cooperation in the hake fishery.The hake fishery between Argentina and China has a broad prospect of cooperation.